Frequency and distribution of HLA-DQB1 alleles from 2076 cord blood samples of the Vietnamese cohort.

Human leucocyte antigen (HLA) alleles are very diverse and characterized by ethnicity. To date, information about the frequencies and distributions of HLA alleles among the Vietnamese population is still limited. In this study, HLA-DQB1 alleles of 2076 cord blood units from individuals belonging to Vietnam's Kinh ethnic people were genotyped using Luminex-based polymerase chain reaction sequence-specific oligonucleotide. The results of the study demonstrated that there were 23 alleles on the locus HLA-DQB1. Among those, there were six alleles with high frequencies of over 5%, including DQB1* 03:01 (35.9%), DQB1* 05:01 (12.8%), DQB1* 03:03 (12.2%); DQB1* 06:01 (7.20%), DQB1* 05:02 (6.62%) and DQB1* 02:01 (5.30%) and five rare alleles with low frequencies of below 0.1%. More importantly, this study for the first time reported the presence of two new rare alleles including DQB1* 01:01 and DQB1* 01:02. Conclusively, this study provided significant information about HLA-DQB1 alleles for further investigations and clinical applications.

Applying sigma metrics to assess quality control processes in the transfusion transmissible infection screening laboratory of a blood center.

In the field of healthcare, quality and efficiency are of paramount importance to ensure the provision of safe and reliable diagnostic services. Blood screening laboratories play a critical role in detecting and preventing the spread of infectious diseases, ensuring the safety of blood transfusions, and supporting medical diagnoses. To enhance the quality of processes in such laboratories, the Six Sigma methodology has gained significant recognition for its ability to systematically identify and minimize variations, thereby improving overall efficiency and reducing errors. This retrospective study aims to explore the application of Six Sigma metrics in the context of blood screening laboratories, providing an in-depth analysis of its implementation, benefits, and challenges. The performance of three serology assays, i.e., anti-HCV, HIV Ag/Ab combo, and HBsAg, using internal quality control (IQC) daily data extracted from six Alinity i instruments (Abbott GmbH, Germany), from February to April 2023, was evaluated. Mean, standard deviation (SD), and coefficient of variation (CV%) was calculated for positive controls. Bias was calculated using peer group data. Sigma metrics were calculated using allowable total error (TEa %) based on difference between the observed mean of the positive control and the s/co cut-off of assay. The observed CV% for positive controls was ≤10%. The TEa% ranged from 66% to 79% for the analytes using the observed mean. All the assays showed Six Sigma performance (σ>6) with and without bias. The study observed that the serology assays showed very high sigma values (σ>6) and thus, simplified statistical quality control (SQC) design based on Westgard Sigma rules could be implemented without compromising blood safety.

Allele and Haplotype Frequencies of HLA-A, -B, -C, and -DRB1 Genes in 3,750 Cord Blood Units From a Kinh Vietnamese Population.

The frequencies and diversities of human leukocyte antigen (HLA) alleles and haplotypes are representative of ethnicities. Matching HLA alleles is essential for many clinical applications, including blood transfusion, stem cell transplantation, and tissue/organ transplantation. To date, the information about the frequencies and distributions of HLA alleles and haplotypes among the Kinh Vietnamese population is limited because of the small sample size. In this study, more than 3,750 cord blood units from individuals belonging to the Kinh Vietnamese population were genotyped using PCR sequence-specific oligonucleotide (PCR-SSO) for HLA testing. The results of the study demonstrated that the most frequently occurring HLA-A, -B, -C, and -DRB1 alleles were A*11:01 (25%), A*24:02 (12.3%), A*02:01 (11.2); A*03:03 (8.95%), A*02:03 (7.81%), A*29:01 (7.03%); B*15:02 (15.1%), B*46:01 (10.7%), B*58:01 (7.65%), B*38:02 (7.29%); C*08:01 (17.2), C*07:02 (16.2%), C*01:02 (15.2), C*03:02 (8.3%), C*15:05 (6.13); DRB1*12:02 (31.0%), DRB1*09:01 (10.47%), DRB1*15:02 (7.54%); DRB1*07:01 (6.68%), DRB1*10:01 (6.63%), respectively, with the highest allele diversity level observed in locus B (93 alleles). The most frequent haplotypes of two-locus combinations of HLA-A-B, HLA-A-C, HLA-A-DRB1, HLA-B-C, HLA-B-DRB1, and HLA-C-DRB1 haplotypes were A*11:01-B*15:02 (7.63%), A*11:01-C*08:01 (7.98%), A*11:01-DRB1*12:02 (10.56%), B*15:02-C*08:01 (14.0%), B*15:02-DRB1*12:02 (10.47%), and C*08:01-DRB1*12:02 (11.38%), respectively. In addition, the most frequent haplotypes of three- and four-locus sets of HLA-A-B-C, HLA-A-B-DRB1, HLA-A-C-DRB1, HLA-B-C-DRB1, and HLA-A-B-C-DRB1 were A*11:01-B*15:02-C*08:01 (7.57%), A*11:01-B*15:02-DRB1*12:02 (5.39%), A*11:01-C*08:01-DRB1*12:02 (5.54%), B*15:02-C*08:01-DRB1*12:02 (10.21%), and A*11:01-B*15:02-C*08:01-DRB1*12:02 (5.45%), respectively. This study provides critical information on the frequencies and distributions of HLA alleles and haplotypes in the Kinh Vietnamese population, accounting for more than 85% of Vietnamese citizens. It paves the way to establish an umbilical cord blood bank for cord blood transplantation programs in Vietnam.

Predominant HLA Alleles and Haplotypes in Mild Adverse Drug Reactions Caused by Allopurinol in Vietnamese Patients with Gout.

Allopurinol (ALP) is commonly used as a drug for gout treatment. However, ALP is known to cause cutaneous adverse reactions (CARs) in patients. The HLA-B*58:01 allele is considered a biomarker of severe CAR (SCAR) in patients with gout, with symptoms of Stevens Johnson syndrome, and with toxic epidermal necrolysis. However, in patients with gout and mild cutaneous adverse drug reactions (MCARs), the role of HLA-allele polymorphisms has not been thoroughly investigated. In this study, 50 samples from ALP-tolerant patients and ALP-induced MCARs patients were genotyped in order to examine the polymorphisms of their HLA-A and HLA-B alleles. Our results showed that the frequencies of HLA-A*02:01/HLA-A*24:02 and HLA-A*02:01/HLA-A*29:01, the dual haplotypes in HLA-A, in patients with ALP-induced MCARs were relatively high, at 33.3% (7/21), which was HLA-B*58:01-independent, while the frequency of these dual haplotypes in the HLA-A locus in ALP-tolerant patients was only 3.45% (1/29). The HLA-B*58:01 allele was detected in 38% (8/21) of patients with ALP-induced MCARs, and in 3.45% (1/29) of ALP-tolerant patients. Notably, although HLA-B*58:01 may be a cause for the occurrence of MCARs in patients with gout, this correlation was not as strong as that previously reported in patients with SCAR. In conclusion, in addition to the HLA-B*58:01 allele, the presence of the dual haplotypes of HLA-A*02:01/HLA-A*24:02 and/or HLA-A*02:01/HLA-A*29:01 in the HLA-A locus may also play an important role in the appearance of ALP-induced MCARs in the Vietnamese population. The obtained primary data may contribute to the development of suitable treatments for patients with gout not only in Vietnam but also in other Asian countries.